1. Field of the Invention
This invention is directed to lubricant compositions having improved antiwear/load-carrying characteristics. More specifically this invention is directed to lubricant compositions wherein such improved characteristics are obtained by incorporating minor amounts of amine derivatives of the reaction product of a dialkylphosphonate and a maleate ester.
2. Description of Prior Art
The metal surfaces of machinery or engines operating under heavy loads wherein metal slides against metal may undergo excessive wear or corrosion. Often the lubricants used to protect the metal surfaces deteriorate under such heavy loads and as a result, do not prevent wear at the points of metal to metal contact. Consequently, the performance of the machine or engine will suffer, and in aggravated cases the machine or engine may become completely inoperative.
There have been many attempts to devise additive systems which would provide satisfactory protection, but these have not always been successful. The phosphonate derivatives of the present invention are believed capable of overcoming some of the deficiencies of prior art additives and to provide lubricating oil compositions with enhanced antiwear characteristics.
U.S. Pat. No. 2,758,971 describes a class of metal phosphonates which are disclosed as having properties which prevent breakdown of oils at high temperatures.
In U.S. Pat. No. 2,792,374 are disclosed the alkali metal salts of certain alkyl alkylphosphonic acids as defoamants in aqueous systems.
U.S. Pat. No. 2,982,727 discloses lubricating oil compositions containing certain salts of oxygen-containing esters of phosphorous. The esters are phosphonates similar to those described in U.S. Pat. No. 2,758,971.